The present invention relates to a self-supporting composite plate, especially a double floor plate with rectangular section and a shallow pan, preferably of sheet metal, serving as an outside wrapper for a material, e.g. anhydrite, with high compression resistance, filled into the pan in a flowable or chargeable state and hardened therein, in which at least the pan bottom is provided with a plurality of punches producing the connection (anchoring) with the filler material, and the pan bottom is also profiled.
A self-supporting composite plate of the above type, of which the outside pan-shaped wrapper also has a smooth bottom, is known from German Pat. No. 2,004,101. Other further developments of this composite plate are also already known (see for comparison the prospectus of the MERO-Werke Company "MERO-Doppelboden" D 488 2/79), in which the floor, with a sheet metal pan serving as the outside wrapper, has reinforcements running from the middle outward, which pass over into a surrounding reinforcement in the border area of the pan bottom. With this composite plate type one also has the pan bottom bulging out from the outside edges to the middle of the bottom. This means that the filler, e.g. anhydrite, is thinnest in the middle of the plate, and is thickest in the area of the four outside edges of the composite plate. It has been shown that, especially when it is used for double floors, the bearing strength and carrying capacity of this composite plate construction is relatively limited and it is not suitable for high stresses. Such double floor plates are mainly known only mounted on uprights located only at their corners, and with very high charges, especially paint charges, critical points are located actually in the middle of the four outside edges of the bottom plate. The use of a stronger sheet metal material for the outside pan-shaped wrapper and/or an increase of the plate thickness cannot be used for various reasons.